Move skins toward modularization

Summary:
Two high-level things happening here:

• We no longer ever need to put meta-UI (content creation, editing, notices, etc.) on live blog views, since this is all in Phame now. I pulled this out.
• On the other hand, I pushed more routing/control logic into Skins and made the root skin a Controller instead of a View. This simplifies some of the code above skins, and the theory behind this is that it gives us greater flexibility to, e.g., put a glue layer between Phame and Wordpress templates or whatever else, and allows skins to handle routing and thus add pages like "About" or "Bio".
• I added a basic skin below the root skin which is more like the old root skin and has standard rendering hooks.
• "Ten Eleven" is a play on the popular (default?) Wordpress themes called "Twenty Ten", "Twenty Eleven" and "Twenty Twelve".

Test Plan: Viewed live blog and live posts. They aren't pretty, but they don't have extraneous resources.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T1373

Differential Revision: https://secure.phabricator.com/D3714